The Evolution of Lactose Tolerance and My Butter Discoveries

From a BBC documentary called Are We Still Evolving? I learned that after the development of farming there was intense selection in Europe for “lactose tolerance” — meaning the ability to digest lactose as an adult, which requires the enzyme lactase. (The technical name is lactase persistence.) The necessary gene spread rapidly. Now most Europeans have the gene. In Ireland almost everyone has the gene. Mark Thomas, an evolutionary geneticist interviewed on the show, who does research on lactose tolerance, said this:

It’s probably the most advantageous characteristic that Europeans have evolved in the last 30,000 years.. . . The advantage that’s been measured is just incredible, absolutely incredible, how big an advantage it was for these early farmers in Europe.

“Why would drinking milk into adulthood be so strongly selected for?” asked Alice Roberts, the presenter. Thomas replied,

Milk has got lots of energy in it, it’s very nutrient dense, it’s got lots of other goodies, like various vitamins, calcium, and so on. Also, it’s a relatively clean fluid, so it’s much better than drinking stream water or river water or well water or something like that. Another advantage is if you’re growing crops you have a boom and bust in terms of the food supply.

Not a word about butterfat — “lots of energy” is true of all fats. The rapid spread, the “incredible” advantage, suggests that milk supplied something resembling a necessary nutrient. As if everyone had been suffering from scurvy and the new gene allowed them to eat citrus — something like that. Such a gene would spread rapidly.

Does milk supply a necessary nutrient? My results suggest that butter — half a stick (60 g)/day — provides two clear benefits: 1. Better brain function. 2. Less risk of heart disease (probably). As far as I can tell, roughly everyone in America would get these benefits because their diets now lack enough of whatever it is. Both benefits reflect invisible problems. Like everyone else, I had no idea my brain function could be substantially improved and had no idea of my rate of progression (narrowing of arteries) toward atherosclerosis. Only because of unusual tests (the arithmetic test and a “heart scan”) did I notice sudden large improvements when I started eating lots of butter — what you’d expected from addition of a missing necessary nutrient. This explains why Thomas and almost everyone else is unaware of these benefits.

Keep in mind that before I started eating butter, I already ate a high-fat low-carbohydrate diet. Yet I wasn’t getting enough of something in butter. I already ate lots of pork fat. Perhaps the saturated fat in butter is better digested than the saturated fat in pork. Or perhaps the fat profile is better.

If lactose tolerance is so helpful, why are most Asians lactose intolerant? My work suggests two answers: 1. Yogurt. Long ago, Asians ate lots of yogurt. I know the Mongols did. There are present-day indications of this. The Chinese appreciate the value of yogurt more than Americans. Yogurt is more common in Chinese supermarkets than American ones. Yogurt makers are better and more common in China than Europe and America. Lots of Chinese make their own yogurt; as far as I can tell, home yogurt making is more popular in China than America. You can buy a cheap good yogurt maker many places in Beijing, unlike San Francisco. Yogurt provided butterfat. 2. Pork. The Chinese, of course, eat far more pork than Europeans. Unlike cows, pigs supply a cut with a large amount of fat: pork belly. I found it easy to get plenty of pork belly in China and eat it as the main course. Difficulty getting pork belly in the Bay Area is what pushed me to eat butter. This view predicts that European farmers raised more cows than pigs.

Anyway, to summarize, the great advantage conferred by lactose tolerance suggests the great value of something in milk if you eat a European-farmer-like diet. My work supports this; it suggests the crucial ingredient is butterfat. Which many Americans carefully avoid!

Note: The danger posed by the high level of AGEs (advanced glycation endproducts) in butter I don’t know about — but of course this danger has nothing to do with why lactose tolerance was so beneficial. My experience so far (the heart-scan improvement) suggests that that ordinary butter is not “artery-constricting”. Presumably AGEs are formed when milk is pasteurized so I would prefer to eat unpasteurized butter.

33 Replies to “The Evolution of Lactose Tolerance and My Butter Discoveries”

  1. AGE’s in food aren’t the same as AGE’s in your blood. Just like cholesterol in your diet doesn’t lead to cholesterol increases in your blood.

  2. Seth,
    the supposed danger of AGEs from butter is based upon degradation of either milk proteins or milk sugar, not sure right now which one. As butter contains little of both, the theory seems to be wrong. I think Stephan Guyenet wrote about the issue recently. AFAIK he thinks that the whole AGE thing is trash

  3. Hi Seth,

    How do you manage to consume half a stick of butter every day on a low carbohydrate diet? I am on a similar diet; if I weren’t I would probably just spread the butter on bread. I enjoy cooking with butter but don’t think that alone will get me close to half a stick per day.



  4. Seth,

    Chris Masterjohn has written a good article talking about AGEs and butter, I think somewhat as a response to Dr. Davis’ post you linked.

  5. I mentioned a commentary on Dr. Davis’ post in my other comment. I should have looked it up, it wasnt’ from Peter at Hyperlipid, it was from Chris at the Daily Lipid. It’s tough keeping my Lipid sources straight. 😉

    Here it is:

    “Is Butter High in AGEs?”

    I wouldn’t get to stressed about the ill effects of butter. I don’t.

    As far as the advantage to butterfat, it’s likely vitamin K2, which was identified by Weston Price as “factor X” that made butter so healthy. Stephen Guyenet has done a bunch of posts on the cardiovascular advantages of K2, and K2 has specifically been shown to prevent aterial calcification in rats (MK4 is K2):

    So keep eating your butter. Btw, as I just started following your blog, I don’t know if you’ve discovered the joys of pastured (grass-fed) butter. It tastes far better, and is available in most Whole Foods I’ve been to. What makes butter taste better or worse? K2 content. Pastured butter has more.

  6. Have you tested butter against seafood, non-farmed, specifically shellfish?

    I’ve noticed an improvement of similar or greater magnitude when I eat shellfish.

    Perhaps that’s the missing nutrient pathway… farming and farm raised animals create deficiencies correctable by seafood or butter.

    I’d like to test the butter/yogurt hypothesis once I’ve got my current problems fully corrected. Right now my vitality scores are acceptable but not stupendous.

  7. Interesting. Things must have changed in China since the 1989 China Study. The authors of that study said about consumption of animal fat (D053 ANIMFAT), “This (6.5 g/day) constitutes a relatively small proportion of total lipid intake (D002:TOTFAT), which averages about 50 g/day.” And about milk (D047: MILK) they said, “Milk is almost never consumed in most parts of rural China. The few places where it is consumed are nomadic herding areas.”

    Have you considered whether there is a specific ingredient of butter which has that impact on you? For somebody like me, whose gut dislikes more than a teaspoon of butter per six hours, have you found a good breakdown of the ingredients of butter? The only unique ingredient that I know about is K2, which supposedly pastured butter has in greater quantity than commercial butter. (It seemed to me that my skin improved once I started taking K2, but it’s not that I had major skin problems to correct, so it’s more of an impression than a measurement.)

  8. The decrease in your heart scan score may most likely be attrituble to varaiblitity in score results; the measurements are calculations based on an algorithm and there is variablity; the score could have been up or down by 10%. It can also change from machine to machine. So i would not base your argument so much on a decreased scan score, but upon the fact it remains unchanged. This alone is quite an accomplishment given plaque can grow by as much as 30% per year. Great job!

    1. Steve, you can see from the graph the average variability. It shows that the decrease in my heart scan score is unlikely to be due to variability. There was no change of machine — both scores were measured on the same machine.

  9. Kirk said:
    Interesting. Things must have changed in China since the 1989 China Study. The authors of that study said about consumption of animal fat (D053 ANIMFAT), “This (6.5 g/day) constitutes a relatively small proportion of total lipid intake (D002:TOTFAT), which averages about 50 g/day.” And about milk (D047: MILK) they said, “Milk is almost never consumed in most parts of rural China. The few places where it is consumed are nomadic herding areas.”

    The actual data is not what Campbell pretends it is in his book (which is a pop nutrition book with no peer review, by the same publisher behind Seven Seasons of Buffy.) In fact, Campbell played fast and loose with the data from Tuoli county whose Uyghur residents eat a diet that’s extremely high in dairy, yet are healthier than the Chinese from counties who don’t.

    Campbell protested being caught out on this by Denise Minger, saying that he was convinced that the residents were “feasting” on the days of data collection, and thus the data for the county was not representative. (He did not explain why only one county would behave this way, while all the others would not.)

    Anyway, for more on why “The China Study” (speaking of the pop culture book, rather than the dataset) cannot be trusted, read here:

    …and here:

  10. Seth great blog. I would like to add more butter to my diet but the thought of eating half a stick straight is unappealing. How do you eat your butter?

  11. 2. Pork. The Chinese, of course, eat far more pork than Europeans.

    In fact, this is not true for all European countries. Germany and Spain are the biggest pork meat consumers in the world. Only third place go to China.

  12. Just did some Googling and found out that natto (Japanese fermented soybeans) contain K2. Being a vegan, I won’t eat butter, but I’ll have to try natto. I understand it’s an acquired taste.

  13. @Tom,

    I am not quoting from the book titled ‘The China Study’ by T. Colin Campbell. I have that book checked out from the library right now and about every 20 pages I am tempted to throw it against the wall whenever Campbell proudly points to something as proof of his assumptions, and meanwhile I remember clearly how Taubes or Minger or one of the paleo bloggers has previously destroyed that argument.

    I took my information directly from the China Study data. I found the data by chasing the links in Denise Minger’s reviews of Campbell’s analysis. My assumption is that the data itself is valid, since both Denise Minger and Ned Kock have used it for statistical analysis. The text extracts I used were taken from the PDF titled ‘Mono_Diet_Survey.pdf’ (which, on the CTSU web page, is labeled ‘Diet survey intake’).

  14. Seth –

    If you had no trouble consuming more butter, how much would you eat daily? Also what kind of trouble are you experiencing? I’ve consumed as much as 1/2 a stick twice a day. It took a few tries for my digestive system to adapt, but now I don’t experience any problems.

    Lastly, where are you finding unpasteurized butter?


  15. Interesting short article from biology writer Robert Dunn on lactose tolerance:

    He says lactose tolerance genes have evolved independently from the European lactose tolerance gene several times in Africa and in other nomadic populations, but they were ignored because none of the genetic databases have much coverage of non-Western populations until one researcher traveled through Africa and did her own genetic sampling.

    Also, there are African tribes that exhibit lactose tolerance without having any known lactose tolerance gene, raising the possibility of population-wide gut flora adaptions.

  16. I’ve had this raw butter from Organic Pastures. It’s good, but expensive and hard to find.

    Note that many of the stores they list on their website as carrying it do not; it’s best to call first.

    For those in Southern California, Co-Oportunity in Santa Monica carries it.

  17. Hi Seth,

    Since butter is just heavy cream whipped, have you tried drinking the appropriate amount of heavy cream, or do you think there is something in the change from one state (liquid) to the other (sort of solid?) that makes it beneficial?

    I know that as far back as the 1950s, bodybuilders used to use heavy cream as a staple of their diets:

    If you really think about it, bodybuilders have been self-experimenting for their data for some amount of decades now. And their self-experimentation which has yielded significant results, as you might predict, is argued against by establishment figures. As an example, you can still see a lot of dietitians (maybe even the majority) argue that extra protein is not needed if someone engages in a heavy weight lifting program. This advice is mostly rejected by almost everyone involved in a heavy weight lifting program that has seen significant results (which are of course, tracked in a log book, like any good self-experiment).

  18. Actually, butter is not simply whipped cream. Butter has the buttermilk (which contains most of the protein that was in the cream) drained off.

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